Windwalker: “short power” "bing jin" tends to break the structure.
Bing jin 掤勁 or some people called it peng jin 棚勁, Bing is an old Chinese word for Quiver cover and my postulation is that it is attached to the quiver and springs open when it is in use. It is an appropriate word to describe springiness in Taijiquan.
Shen (1963, p15) described bing jin as the general characteristics of stretchy and stringy in all the 8 different techniques (bīng, lǚ, jǐ, àn, cǎi, liè, zhǒu, kào) and also as the techniques which is the outward rotation of the arm with the centre of palm from pointing inward to pointing outward. For lie jin 挒勁, is described as a short distance strike or maybe “short power” and as an example of store and issue.